According to the CDC (the Centre for Disease Control and Prevention), in America the leading cause of death in men (of all ages) is Heart disease. Approximately 1 in every 4 men will die of heart disease which is sad as it is preventable in up to 80% of cases.[1,2] It's important then that you continue to encourage your husband to see his doctor.
I would note though that often it is not the worst case scenario (e.g. fear of dying) that spurs people on to action, but rather positive encouragement and hope for better things. If he is overweight or run down etc., then encouraging him to see his doctor for remedies to feel better and healthier will probably enthuse him more than discussing negative statistics.
 CDC Men's Health (www.cdc.gov/men/lcod/index.htm